Grass Quality Supporting 14–15 Litres of Milk
Fresh grass analysis carried out in Lifford on 2nd July 2026 highlights the current feeding value of grazing conditions. The results are typical for July in the west of Ireland, where frequent rainfall leads to grass with a lower dry matter content. As the grass contains more water, nutrient concentration is diluted, reducing the amount of dry matter cows can consume.
Grass Analysis Results
| Parameter | Result |
| Dry Matter | 15.08% |
| Protein | 25.6% |
| NDF | 43.15% |
| DMD | 84.31% |
| Metabolisable Energy (ME) | 12.5 MJ/kg DM |
Based on this analysis, a 600kg dairy cow consuming approximately 14kg of dry matter (DM) should be capable of producing 14–15 litres of milk per day from grass alone.
For first-calving heifers, expected production would typically be around 2 litres lower, reflecting their continued growth requirements.
Why Grass Intake Matters
A cow’s milk production from grass is directly linked to how much grass she can consume. Grass quality is only part of the equation; the intake potential of the sward is equally important.
Grass intake depends on:
- Sward height
- Sward density
- Dry matter percentage
- Grazing conditions
- Weather
Under normal conditions, a dairy cow:
- Grazes for around 10 hours per day (600 minutes)
- Takes approximately 60 bites per minute
- Consumes 0.4–0.5g of DM per bite
Dry Matter Intake (DMI) = Intake per bite × Bites per minute × Grazing time
Example:
0.4g × 60 bites × 600 minutes = 14,400g, or 14.4kg DM per day
This level of intake supports the predicted 14–15 litres of milk from the current Lifford grass sample.
Weather Has a Major Impact
Dry grazing conditions allow cows to maximise grass intake.
When conditions become wet:
- Grass dry matter falls as plants contain more water.
- Grass becomes more heavily soiled.
- Palatability declines.
- Cows consume less dry matter.
As a result, milk production from grazed grass can be up to 2 litres per cow per day lower under normal or challenging grazing conditions compared with ideal conditions.
Seasonal Milk Production from Grass
The milk production potential of grazed grass naturally changes throughout the grazing season.
| Month | Potential Milk Yield |
| April | 18–20 litres |
| May | 22–24 litres |
| June | 21–22 litres |
| July | 18–19 litres |
| August | 16–17 litres |
| September | 13–15 litres |
The Importance of Dry Matter
Grass with a Dry Matter below 18% significantly limits intake.
Research and field experience show that:
- For every 1% drop below 18% DM, grass intake falls by approximately 0.34kg DM per cow per day.
Typical spring grass often contains less than 18% dry matter, meaning cows must physically consume much larger quantities of fresh grass to achieve the same nutrient intake.
This reduction in intake can have a significant impact on milk production.
Bridging the Nutritional Gap
Where grass dry matter is low or energy demand is high, concentrates can play an important role by:
- Maximising dry matter intake
- Bridging the energy deficit during early lactation
- Supporting higher milk yield
- Improving milk constituents
Tailored Nutrition from Smyths Daleside
Every dairy system is different, and feeding strategies should reflect herd performance, grazing conditions and production goals.
Smyths Daleside offers a comprehensive range of dairy feeds designed to suit a wide variety of farming systems. Our experienced sales representatives can help identify the most suitable feeding programme for your herd.
For further advice, please contact your local Smyths Daleside representative or call the office on +353 (0)74 917 1300.